Like I’ve said previously, I’m very thankful of the tons of contributors that made this step possible. From the early testers, over the many new KDevelop contributors who helped a lot in porting our code base to Qt 5 and KF5, to the people that worked on improving kdev-clang and all the other areas. It’s a great feeling to finally release this beast. A year ago, just after we started in this process, I still wasn’t too sure we can pull it all off. Now, look where we are :) “Just” a few more weeks of polishing and I’m positively sure KDevelop 5.0.0 will be a really good milestone.

That said, I also want to express my thanks towards the KDE e.V. which graciously sponsored our recent KDevelop/Kate sprint in Berlin. We rented a flat for the 8 hackers that visited Berlin and had a productive five days directly after the Qt World Summit. Personally, I worked on kdev-clang and polished it a bit more in the preparation of the first beta release. One handy feature I added is the display of size information about classes and member variables, displayed in the image to the right.

If you want to give back to the KDevelop community, please consider a donation to the KDE e.v., which is used for our yearly developer sprints and the Akademy conference.

last week, I handed in my Master’s thesis. I was studying Physics for about 7.5 years now. I started using KDE 3.5.x while still in school and in my first student job as a web developer. At university, I taught myself C++ while working as a sysadmin at the faculty, in order to contribute to Kate, Quanta and KDevelop. I quickly discovered that Physics wasn’t so much my thing but the German education system doesn’t make it easy to switch fields. Thus, I endured and continued. And I kept coding though, mostly in my spare time, but also while working part-time for KDAB. Now, all these years later, I’m one of the official maintainers of KDevelop, and also contribute to KF5, esp. KTextEditor regularly. I created tools such as Massif-Visualizer and heaptrack. I became a Qt approver and maintainer of the Qt WebChannel module. And, starting from May this year, I’ll finally be working full-time for KDAB. Oh, how things have changed! Just compare Plasma 5.2 today to the KDE 4.0 alpha 1 or whatever it was that I tried in 2007 - a difference of night and day!

Thanks KDE, for heavily contributing to who I am today! Numerous people within the community have taught me so much about so many things. Without you all, I might still be programming websites in PHP or sitting in a lab… I’m so grateful this is not the case!

Starting this friday I’ll be gone on a long vacation to Ecuador and Columbia. I’ll try to sieve through my email when I come back on the 10th of April. I’m super excited to see what will happen to me, but also to all my favorite software projects during this time!

I’m happy to be back so soon with a status update on heaptrack: It is now possible to attach to an already running process!

Thanks to the great help from Celelibi on StackOverflow, I managed to achieve this important goal.
Once you know what to do, it is actually extremely simple to patch a running process. I use GDB to attach to the process, then call dlopen to load
a special heaptrack library for runtime-injection. Then I call an initialization function which takes the desired output file as a parameter, and then
detach GDB. To actually overwrite malloc & friends, one can leverage dl_iterate_phdr and the public ELF API on Linux systems to find dynamic sections that reference one of our target symbols in their global offset table (GOT). This can then be rewritten to point to our custom hooks. Some refactoring later, which stabilized the shutdown sequence to allows multiple heaptrack attach/detach sequences, we can now do this:

heaptrack -p $(pidof <yourapp>)

# wait

^C

heaptrack_print heaptrack.<yourapp>.$$.gz | less

This is a great help when you want to investigate why the memory consumption of your application suddenly rises. No need to restart the app, just attach heaptrack and wait for some, then kill it and heaptrack_print the outputfile.

with a tingly feeling in my belly, I’m happy to announce heaptrack, a heap memory profiler for Linux. Over the last couple of months I’ve worked on this new tool in my free time. What started as a “what if” experiment quickly became such a promising tool that I couldn’t stop working on it, at the cost of neglecting my physics masters thesis (who needs that anyways, eh?). In the following, I’ll show you how to use this tool, and why you should start using it.

This is a special release, as it marks the end of the KDE 4 era for us in
terms of feature development. We will continue to support this release in the
long-term with bug fixes though. New things and fundamental changes will only
happen in the frameworkified master branches from now an.

Yesterday my Profiling 101 workshop took place at this years Akademy in Brno. The room was packed and I got good feedback, so I hope you all learned something new :)

During my workshop, I showed you how to improve the performance of a word-count application which also creates a word histogram and finds the longest word of a file. I tried to put as many performance bottlenecks as possible into the original code base, which you can find here:

git clone git@git.kde.org:scratch/mwolff/akademy-2014.git

Instead of uploading my useless slides full of meme images, instead I’m now pushing my optimized code branch. I urge everyone to review the commits I did and read the individual commit messages (Note: read this log from bottom to top). There are many useful tips and tricks in there. I furthermore plan to create a techbase article with the most important notes on how to use profilers for a given job. I’ll write another blog post once I’m done with that.

Furthermore, if you want to learn profiling, I think my scratch repo up there is a good coding kata. Branch off from the master branch and create your own optimized one. Use profilers such as Valgrind callgrind and Linux perf for CPU runtime. Try out Massif and heaptrack for memory.

I hope together we can make KDE software much faster. There are probably many low-hanging fruit throughout our large codebase. If you have any question, please do ask me.

Cheers, enjoy the rest of Akademy. Many thanks to the organizers, sponsors and the KDE e.V.!

I have the pleasure to attend Akademy this year again. From my past experience, I’m really looking forward to have a good time again. Lots of hacking, meeting known and unknown faces, drinking beer and socializing ahead! I also love that it’s in a (to me) new country again, and wonder what I will see of the Czech Republic and Brno!

This year, the conference schedule is a bit different from the past years. Not only do we have the usual two days packed with interesting talks and keynotes. No - this year there will also be workshops on the third day! These are more in-depth talks which hopefully teach the audience some new skills, be it QML, mobile development, testing, or … profiling :) Your’s truly has the honor to hold a one-hour Profiling 101 workshop.

I welcome all of you to attend my presentation. My plan, currently, is to do some life demoing of how I profile and optimize code. For that purpose, I just wrote a (really slow and badly written) word count test-app. I pushed the sources to kde:scratch/mwolff/akademy-2014.git. If you plan to join my workshop, I encourage you to download the sources and take a shot at optimizing it. I tried my best to write slow code this time, to leave plenty of opportunity for optimizations :) There are many low-hanging fruits in the code. I’m confident that I’ll be able to teach you some more advanced tips and tricks on how you can improve a Qt application’s performance. We’ll see in the end who can come up with the fastest version :)

During my workshop, I’ll investigate the performance of the wordcount app with various tools: On one hand this should teach you how to use the powerful existing opensource tools such as Linux perf and the valgrind suite. I will also show you Intel VTune though, as it is still unparalleled in many aspects and available free-of-charge for non-commercial usage on Linux. Then, I’ll present a few of my own tools to you, such as heaptrack. If you never heard of some of these tools, go try them out before Akademy!

I’ll see what else I’ll fit in and maybe I’ll extend my akademy-2014.git scratch repository with more examples over the next days.